ABSTRACT
A graphically-oriented MATLAB program written by the authors facilitates teaching real-world digital signal
processing concepts such as quantization of digital filter coefficients that occur in fixed-point processors, for
example the widely used TMS320C5x. While many universities have or plan to buy the inexpensive floating-point
TMS320C31 DSKs for pedagogical reasons, this MATLAB program simulates certain fixed-point effects on these
floating-point devices and eliminates the need to purchase expensive specialized software programs or extra
hardware. The program described in this paper provides an interactive graphical user interface that communicates
directly with the DSK, and demonstrates in real-time how both coefficient quantization and filter implementation
affect filter performance, without the need for tedious programming of the TMS320C31.

1. INTRODUCTION
Modern software tools such as MATLAB greatly facilitate the professor's ability to demonstrate
the concepts of digital signal processing (DSP) in class, and to assign realistic projects to
reinforce these concepts.1-3 An increasing number of DSP textbooks are becoming available
which take advantage of this ability,4-8 and a growing trend is for DSP concepts to be introduced
earlier in the curriculum.9 These concepts can be further reinforced, and greater interest
generated by the students, if they can be easily implemented in real-time on modern DSP
hardware.10 Affordable hardware is now available to schools: Texas Instruments, for example,
markets DSP Starter Kits (DSKs) for $99.11 While fixed-point processors are more prevalent in
industry12 (albeit floating point is gaining in use), floating-point processors are becoming more
popular for schools due to pedagogical reasons. We will examine how MATLAB, already
accepted as a powerful learning tool for DSP, can be closely integrated with a DSK for teaching
purposes while avoiding the tedium of manually programming the DSP processor.

1.1 Teaching with MATLAB
MATLAB is an excellent learning tool for DSP education, enabling an easier transition for the
student from theory to practice. This greatly facilitates a student’s ability to apply signal
processing concepts to real-world DSP hardware such as the widely-used Texas Instruments
TMS320C series of fixed-point and floating-point DSP microprocessors. In particular, the
sptool program supplied with the latest release of the student edition of MATLAB (version 5) and
also available in the latest Signal Processing Toolbox (version 4.x, written for MATLAB 5.x
Professional) provides an excellent interactive graphical user interface (GUI) for designing both